Method of nitrating cellulose



wmw NNNN G. JUER METHOD OF NITHATINGv CELLULOSE Filed June 5. 1923 Nov. 171 1925' Patented Nov. 17, 1925.

1,562,093 fllfl-llTilD STATES-PATENT OFFICE.

" GEORGE JUER, OE HOPEWELL, VIRGINIA, AssIGNoR To TURIZE ARTIFICIAL sILx COMPANY OF AMERICA, A CORPORATION OE DELAWARE.

METHOD OF NI'JIItA'JTIIl'G CELLULOSE.

Application med :une 5,1923. serial N. 643,548.

T all whom/t may concern: l Be it known that I, GEORGE J UER, recently a subject of the former Austro-Hungarian Empire, and now a resident of Hopewell, inthe county of Prince George, in the State of Virginia, have invented certain new and useful Improvements in Methods of Nitrating Cellulose, offwhich the following is a true and exact description, reference ,being y had'to the accompanying drawing, which forms a part thereof.

My invention relates to the nitration of cellulose, Ordinarily cotton. As heretofore v carried on, this operation has been effected in mixing pots intov which the cotton and the acids are fed together and' in'which they are thoroughly mixed, the different batches re.- maining in the mixing pots until the nitration is'complete, that is to say, until the cottonand the acid ceases to'react upon each l other. Prolonged mixing during the nitrationoperation 1s found to have a tendency to break the cotton which is highlyV detrimental to the subsequentn handlingA of the nitrated material wh1le,'if the mixing is Anot continued,.uniform lnitration is apt to be impaired owing to the tendency of the cotton to sink to the bottom of the pot Iand of the acids to form layers of erent density; The lObject of my Invention is to provide a method in 'which the. nitration of the cotton can take place with great uniformity, with' all necessar and the 4least harmful mixing of the batc and in a plant of great compactness and simplicity requiring much less laborin its operation than has heretofore 'been necessary. My method. consists, broadly speaking, in mixing batches ofcellulose v and A'acids in mixing pots and in the Ordinary 40 Way and then char 'ng the partly 4nitratedbatch into a rotatab e horizontal-cylinder by the 'rotation of which, preferably occurring at intervals and not continuously, the batch44 istumbled so las to effect the necessary mix- 4a ing of the acids and' cellulose in the entlest and least injurious -way until' the nitratlon l is complete.

l B lpreference and for the best-resultsl I empio y a long horizontal cylinder, the bot- 50 tom' of which is divided intoj chambersA of to hold and keep entirely;l

chambers of a holding capacity of from three to four times the bulk of the batch. In this apparatus, which forms the subject matter of my Letters Patent No. 1,485,507, March 4, 1924:, the cylinder is rotated intermittently between the delivery to it of. batches from the mixing pot and each batch 1s contained in the cylinder andintermittently tumbled as described for a sufficient time to effect complete nitration. My invention will be bestunderstood as described A in connection with the drawing 'which illus- .trates an apparatus adapted forr its practice, the drawing being an elevation for the most part in-section.

A indicates the flooring of aroom at a higher elevation than the'nitrating apparatus in which the cotton to be nitratedis stored fand from which leads a hopper B provided with a feeding device indicated lat C. B indicates the delivery end of the hopper opening as shown into aho'od'D which extends over the top of the mixing pot.

D is an opening in thetopof the4 hood` through which the shaft of the mixing device extends, D2 is an opening in the hood z through which an acid pipe 1s introduced into the hood'and D3 is a pipe or conduit leading from the hood and connected withv a fan, not shown, for drawing off the acid fumes which rise in the hood from the-mixing pot. E indicates the housing for the mixing apparatus, E indicating a' driving shaft which, as shown, is connected by a mitre wheel E2 and the mitre wheel E3 with `the shaftE which through a mitre gear E5 anv drives a mitre gear E6 from which extends a shaft `E7 connected so as to rotate with the gear E but free to move u and down in it,

the lower part of this sha t being threaded as indicated at E? and thethreadedportion of the shaft being engaged with a threaded portion E9 of the housing E.- E10 indicates the mixing wheel supported at the bottom of the shaft E7. This part of the apparatus is not new with me and-is not' shown in detail. It will be understood that the shaft E4 is rotated alternately in Opposite directions so that the mixing device' E1o also rotating in Opposite directlons will alternately rise and' fall in its downward movement pressing the cotton entering the-hood' through the 4hopper into the mixin 'potand while in the pot acting to mix t e cotton thoroughly with ithe acid.

I' standards'G which support the trunnions Alo H of the mixing pot yindicated at H. I is a hopper secured in the end of the cylinder J and opening intothe cylinder through its lower end indicated at I. I2 is a closure for thehopper which is opened when the charge is being dumped into it from the mixing pot and which should remain closed duri-ng the rotating movement of the cylinder. J is Athe cylinder to the inner wall of which is secured the helically bent plate@ indicated at J The depth and pitch of this helix should be such as will divide the lower portion of the cylinder into a series of containing chambers indicated in the drawing by the numerals from 1 to 12 and each of such dimension as to hold and keep-se arate a charge delivered into the cylinder rom the mixing pot. I consider it advisable that each chamber; 1, 2, etc., should have a capacity of about three times that of the mixing pot. The end of the helix indicated at J 2 is formed so as to lead directly into the delivery passage J 3 at the rear end of the cylinder. J 4 and J 5 are circular rings or bearings secured to the cylinder (J and through which itis supported on rollers indicated at J7 and J8. J6 is an annular rack or gear wheel secured to the cylinder J and engaged with the pinion J 9 on a shaft J10 to which, as shown, are secured fast and loose pulleys J11 and J12. K is a delivery condult with which the delivery end J 3 of the cylinder connects as shown and which leads into a centrifugal wringer indicated at L and which may be of ordinarily used construction from which the dried nitrate of cotton is delivered into a stora e chamber M. N is a conduit leading rom the upper end of the delivery conduit K to a fan indicated at N,"from which leads an outlet conduit N 2.

vIn operation a measured chargerof acid is delivered into the mixin pot H and a measured charge of cotton 1s dumped into the hopper B. The feeding device C and mixing device E10 are then set in operation, the cotton being Vfed with uniform determined speed into the mixing pot and the mixer E1 in its downward movement pressing the cotton which has passed the deliveryend B of the hopper downl into the mixing pot H and thoroughly stirring it into the acid. When the full -charge of cotton has been delivered into the mixing pot and thoroughly mixed with the acid therein the cylinder J brought to the position shown in the drawing with its hopper I in proper position to receive the charge from the mixing pot has the contents of the mixing pot dumped into it, the charge occupying the divislonal chamber indicated at l and thereafter the cylinder J is rotated through one complete revolution so that the charge .just dumped into it will occupy the chamber indicated at 2. A new charge of acid and cotton is then mixed in the mixing pot and dumped into the chamber 1 of the cylinder J and so on. The number of chambers into which the cylinder J is divided by the spirally twisted plate is such as to insure that each charge progressively delivered to the cylinder and progressively moved along the length of the cylinder should remain in the cylinder for a sufficient length of time to insure its complete nitration so that when the charges are delivered from the end chamber 12 into the outlet passage J 3 and through the conduit K into the wringer L nitratio'n will be completely efected.

It will be obvious that my mechanism is such that a single mixing pot and mixing apparatus can be kept in practically continuous operation to thoroughly mix the cotton and acid together and begin the nitrating operation while the greater part of the operation of nitration goes on in the mixing cylinder which keeps the charges from the mixing pot separated from each other and retains each charge for a sufficient length of timel to insure the complete nitration of the cotton before delivering it to.`

the drying apparatus.

The leading off of fumes from the hood over the mixing pot and from the conduit K is a detail of practical importance enabling my apparatus to be used-without exposing the workmen to the acid fumes which arise l from the mixing 'pot and cylinder.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is: f

The method of nitrating cellulose which consists in thoroughly mixing cellulose and acids in a mixing pot so as to efect a partial nitration of the cellulose, charging the partially nitrated cellulose and admixed acids into a rotatable cylinder and. tumbling the batch by rotating the cylinder until the nitration is complete. 1- I c GEORGE J UER 

